The present invention relates to a shaft engine having cylinder shafts reciprocated by the piston thereof to move a crank shaft for power output, wherein the cylinder shafts comprise air passages for guiding a fuel gas into the cylinder and for sending exhaust gas out of the cylinder respectively.
The engine of a motor vehicle is generally comprised of a cylinder having a piston or pistons reciprocated, by means of the burning of a fuel gas in the cylinder, to turn a crank shaft. This structure of engine further comprises an exhaust piping system, intake and exhaust valves, and an exhaust cam. Therefore, this structure of engine is complicated and difficult to maintain. Because of a complicated structure, the manufacturing cost and weight of this engine are relatively increased. Further, in a two stroke engine, the exhaust and intake strokes are simultaneously performed when the piston is moved to the lower limit, and therefore the problem of low combustion efficiency and high exhaust emissions cannot be eliminated.